title: Sleep-dependent neurophysiological processes in implicit sequence learning.
abstract: Behavioral studies have cast doubts about the role that posttraining sleep may play in the consolidation of implicit sequence learning. Here, we used event-related fMRI to test the hypothesis that sleep-dependent functional reorganization would take place in the underlying neural circuits even in the possible absence of obvious behavioral changes. Twenty-four healthy human adults were scanned at Day 1 and then at Day 4 during an implicit probabilistic serial RT task. They either slept normally (RS) or were sleep-deprived (SD) on the first posttraining night. Unknown to them, the sequential structure of the material was based on a probabilistic finite-state grammar, with 15% chance on each trial of replacing the rules-based grammatical (G) stimulus with a nongrammatical (NG) one. Results indicated a gradual differentiation across sessions between RTs (faster RTs for G than NG), together with NG-related BOLD responses reflecting sequence learning. Similar behavioral patterns were observed in RS and SD participants at Day 4, indicating time- but not sleep-dependent consolidation of performance. Notwithstanding, we observed at Day 4 in the RS group a diminished differentiation between G- and NG-related neurophysiological responses in a set of cortical and subcortical areas previously identified as being part of the network involved in implicit sequence learning and its offline processing during sleep, indicating a sleep-dependent processing of both regular and deviant stimuli. Our results suggest the sleep-dependent development of distinct neurophysiological processes subtending consolidation of implicit motor sequence learning, even in the absence of overt behavioral differences.
authors.affiliation: Neuropsychology and Functional Neuroimaging Research Unit at CRCN - Center for Research in Cognition and Neurosciences and UNI - ULB Neurosciences Institute, Université Libre de Bruxelles (ULB), Brussels, Belgium.
authors.forename: Charline
authors.initials: C
authors.lastname: Urbain
authors.forename: Rémy
authors.initials: R
authors.lastname: Schmitz
authors.forename: Christina
authors.initials: C
authors.lastname: Schmidt
authors.forename: Axel
authors.initials: A
authors.lastname: Cleeremans
authors.forename: Patrick
authors.initials: P
authors.lastname: Van Bogaert
authors.forename: Pierre
authors.initials: P
authors.lastname: Maquet
authors.forename: Philippe
authors.initials: P
authors.lastname: Peigneux
mesh_terms: D001921:Brain / Q000502:physiology; D001931:Brain Mapping; D002940:Circadian Rhythm; D003627:Data Interpretation, Statistical; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D015233:Models, Statistical; D010100:Oxygen / Q000097:blood; D011930:Reaction Time / Q000502:physiology; D012647:Self-Assessment; D012691:Serial Learning / Q000502:physiology*; D012890:Sleep / Q000502:physiology*; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D010100:Oxygen